Suture locking device

ABSTRACT

The invention disclosed is a device for locking a suture in place without the need for tying knots once the suture is placed within tissue. The device comprises a locking ring, the locking ring comprising a series of laminated sheets having an aperture formed to allow the suture to pass when pulled in a first direction, but formed to lock the suture in place when the suture is pulled in an opposite direction.

[0001] This application is a divisional of U.S. patent application Ser.No. 09/474,416, filed Dec. 29, 1999, which claims priority under 35U.S.C. § 119(e) to U.S. Provisional Application No. 60/114,170, filedDec. 30, 1998, which is expressly incorporated by reference herein.

FIELD OF THE INVENTION

[0002] The present invention relates to a device for locking a suture invivo, more particularly to a device for locking a suture in vivo withoutthe need for tying knots once the suture is placed within tissue. Thepresent invention also relates to a method for using such a device toapproximate tissue and to lock the suture in place.

BACKGROUND AND SUMMARY OF THE INVENTION

[0003] It is known in the art to approximate damaged or torn tissue byuse of a suture. In many instances, the suture is looped through tissue,and the two ends are then secured together. Prior art methods forsecuring a suture include tying knots. Other methods include providing afilament having various protruding portions and securing the filamentagainst one of those protruding portions. See, e.g., U.S. Pat. No.5,520,691, incorporated herein by reference. Still other prior artmethods include compressing the suture between a cylinder/piston wallinterface. See, e.g., U.S. Pat. No. 5,630,824, incorporated herein byreference. Such sutures may be used to approximate damage in soft tissueor to attach soft tissue to bone.

[0004] The present invention provides a suture locking device thatrelies on frictional forces. In one embodiment, a suture is passedthrough an anchor having a tapered or stepped cannula. The suture isthen passed through tissue, may be passed through or around a secondanchor located on the opposite side of the defect, and looped backthrough the cannula. One end of the suture may be provided with a knotor bead. As the surgeon pulls on the second end, the knot or bead entersthe cannula, pulls the two anchors toward each other, then both strandswedge tightly in the cannula. In an alternative embodiment, instead of aknot or bead, a slip knot is provided on the first end. The second endmay be threaded through the slip knot. Again, as the surgeon pulls onthe second end, the knot will enter the tapered or stepped cannula, pullthe two anchors together, and wedge both strands tightly within thecannula.

[0005] In another embodiment of this invention, a locking ring is usedto secure the sutures to the anchor. The anchor may be provided with asplit section and the suture would pass through this split section. Thelocking ring may be of either the push-type or the pull-type, and whenengaged, the locking ring would force the portions of the split sectiontogether, thus wedging the split section together and locking the suturestrands in place. The split section may be provided with teeth to gripthe suture better.

[0006] In another embodiment, the suture may be secured with a snapgroove provided on the anchor. As with the locking ring arrangement, theanchor would be provided with a split section. A tooth on one section issized and shaped to mate with a groove on the other section. When thetooth is snapped into the groove, the suture strands would be lockedinto place.

[0007] An additional embodiment may employ a wedge design. In such adesign, the anchor may be provided with a cylindrical cannula, and awedge would be provided to fit tightly within the cannula. The wedgeitself may be partially cannulated to aid in insertion, but the suturewould also, in part, pass along the exterior of the wedge, so thatfrictional forces would secure the suture between the wedge and theinside of the cannula, in order to lock the suture in place.

[0008] Alternatively, the suture locking device may comprise laminatedsheets. Slits in the laminated sheets would allow the suture to pass inone direction with little resistance. However, the sheets would bedesigned to lock on the suture when the suture is pulled in the reversedirection. Thus, the surgeon could pull on the suture to tighten it, andthe suture would remain locked in place.

[0009] Some embodiments of the present invention are described forsituations in which the suture is looped through tissue, and two ends ofthe suture must be secured. Other embodiments are described in whicheach end of the suture strand is secured independently. It will beunderstood that the invention may be employed in situations involving asingle strand or with multiple suture or filament strands. Also, it willbe understood that the scope of this invention is not limitedspecifically to securing two ends of a suture within one lockingmechanism.

[0010] The anchor may be made of biocompatible material such asstainless steel, titanium, cobalt chrome, and polyethylene. Preferably,biodegradable materials may also be used, including poly lactic acid andpoly lactic-glycolic acid. Other biodegradable materials are known. See,e.g., U.S. Pat. No. 4,976,715, hereby incorporated by reference. Thesuture may be made of resorbable or non-resorbable material, as areknown in the art.

[0011] Therefore, in one embodiment of the present invention, a deviceis provided for locking a suture in place, the device comprising ananchor having a cannula, the cannula for receiving a suture, and alocking mechanism for locking the suture in place. The locking mechanismmay comprise a bead, knot, or wedge sized to wedge within the cannula orthe locking mechanism may comprise a locking ring. The cannula may becylindrical, tapered, or stepped.

[0012] In another embodiment of the present invention, a device isprovided for locking a suture in place, the device comprising an anchorhaving a cannula and a locking mechanism. The cannula is for receivingthe suture, and the locking mechanism is for locking the suture withinthe cannula. The locking mechanism may comprise a locking ring or a snapgroove.

[0013] In still another embodiment of the present invention, a devicefor locking a suture in place is provided, comprising an anchor having afront edge and a rear edge, the anchor having a cannula extending fromthe front section to the rear section, and a locking mechanism. In thisembodiment, the suture comprises a first end and a second end, thesuture extending through the cannula of the anchor from the rear edge tothe front edge, through a portion of tissue, and extending back throughthe cannula from the front edge to the rear edge, the second endprotruding from the rear edge of the suture. The locking mechanismcomprises a bead located at the first end of the suture, and the beadsized to fit snugly within a portion of the cannula. Pulling the secondend of the suture causes the bead to travel toward the front edge of theanchor and to wedge within the portion of the cannula, thereby lockingthe suture in place.

[0014] Additional features of the present invention will become apparentto those skilled in the art upon consideration of the following detaileddescription of preferred embodiments exemplifying the best mode ofcarrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a cross-sectional view of a locking device of thisinvention, in which the locking device comprises an anchor with atapered cannula and a suture with a bead, shown in combination with asecond anchor;

[0016]FIG. 2 is a cross-sectional view of the anchor of FIG. 1, with thesuture in locked position;

[0017]FIG. 3 is similar to FIG. 2, except that the cannula is steppedrather than tapered;

[0018]FIG. 4 is similar to FIG. 1, except that a slip knot replaces thebead;

[0019]FIG. 5 is a cross-sectional view of another embodiment of thisinvention, in which the suture locking device comprises a pull lockingring in combination with a cannulated anchor;

[0020]FIG. 6 is similar to FIG. 5, except showing the device in a lockedposition;

[0021]FIG. 7 is similar to FIG. 5, except showing a device with a pushlocking ring;

[0022]FIG. 8 is similar to FIG. 7, except showing the device in a lockedposition;

[0023]FIG. 9 is a cross-sectional view of an embodiment of thisinvention employing a snap lock design;

[0024]FIG. 10 is a cross-sectional view of still another embodiment ofthis invention which employs a wedge design;

[0025]FIG. 11 is a perspective view of an additional embodiment of thisinvention, employing a laminated sheet design;

[0026]FIG. 12 is a cross-sectional view of FIG. 11, along line 12-12;

[0027]FIG. 13 is a cross-sectional view of a meniscus of a knee, showinga defect approximated by a suture that is locked into position by usingtwo locking devices of FIG. 11.

DETAILED DESCRIPTION OF THE DRAWINGS

[0028]FIG. 1 shows generally a suture locking device of this inventionin a combination as the device may be employed. In the illustrativeembodiment, a suture 40 passes through a cannula 22 in an anchor 20. Thesuture loops through or around a second anchor 80, and then returnsthrough cannula 22. In use, anchor 20 and second anchor 80 may belocated on opposite sides of a soft tissue defect (not shown), andsuture 40 may be used to pull the defect together. Alternatively, secondanchor 80 may be located within or beyond a portion of bone (not shown),and anchor 20 may be used to attach soft tissue to the bone. Otherapplications are also possible.

[0029] As shown, second anchor 80 is provided with two holes 82, 84.Suture 40 extends from first anchor 20 to second anchor 80, loopsthrough first hole 82 and returns through second hole 84 back to firstanchor 20. Alternatively, second anchor 80 may be provided with one holethrough which suture 40 passes before returning to first anchor 20. Inother embodiments, second anchor 80 may be provided with a singularcannulation lengthwise with the suture 40 extending therethrough, or thesecond anchor 80 may be provided without any holes, and the suture 40may merely loop over second anchor 80. In some situations, a secondanchor may not be necessary, and suture 40 simply loops over or throughtissue.

[0030] In the embodiment shown in FIG. 1, the anchor 20 is configured tobury partially or totally into tissue, for use in tissue repair whereinterference with the tissue surface is not desirable. Thisconfiguration may be desirable for use on surfaces such as the innersurface of the meniscus of the knee, where a protruding anchor mayinterfere with joint articulation. However, as illustrated in FIGS.10-13, anchors which are configured to abut, without entering, tissueare also within the scope of this invention. The combination illustratedin FIG. 1 is meant merely as an example of a suture/anchor combinationthat may be locked with the suture locking device of this invention.

[0031] Referring still to FIG. 1, suture 40 is provided with a first end42 and a second end 44. As shown, first end 42 is provided with a bead46, and the cannula 22 is tapered. As the surgeon pulls on the secondend 44 of suture 40, the bead 46 enters the cannula 22. With continuedpulling, the bead 46 pulls anchor 20 toward second anchor 80, forexample, to close a defect in tissue or to secure soft tissue to a bone.When anchor 20 is fully seated, bead 46 wedges into cannula 22, and bead46 secures second end 44 within the cannula 22.

[0032]FIG. 2 illustrates the anchor 20 of FIG. 1 after the suture 40 hasbeen pulled tight and locked into place. FIG. 3 illustrates analternative embodiment wherein the cannula 22 is stepped, rather thantapered. As with the embodiment illustrated in FIG. 2, when suture 40 ispulled tight, the bead 46 locks the suture 40 in place. Bead 46 may bepermanently affixed to suture 40 in any number of ways, as are known inthe art. Alternatively, suture 40 may be manufactured with bead 46 as aprotuberance integral with the suture filament. Also, bead 46 may be aknot in suture 40 of sufficient size to lock suture 40 in place.

[0033] Another embodiment is illustrated in FIG. 4. The first end 42 ofsuture 40 is provided with a slip knot 48. As with the embodiment shownin FIG. 1, the anchor 20 is provided with a cannula 22 that may betapered or stepped. Preferably, second end 44 is fed through loop 49 ofslip knot 48, and the loop 49 may be tensioned slightly. As the surgeonpulls on the second end 44, slip knot 48 will travel distally along thesecond end 44, until slip knot 48 begins to push the anchor 20 towardthe second anchor 80. As with the bead 46 of FIG. 1, slip knot 48 wedgesin cannula 22, locking the suture in place.

[0034] FIGS. 5-8 relate to embodiments employing locking rings. FIGS. 5and 6 involve a pull locking ring with FIG. 5 illustrating the openposition and FIG. 6 illustrating the locked position. As illustrated inFIGS. 5 and 6, anchor 20 is provided with cannula 22. Preferably, rearsection 24 of anchor 20 is split into first and second rear portions 26,28, to define split gap 30. An annular locking ring 70 is providedaround middle section 25. Once anchor 20 and suture 40 are properlypositioned, locking ring 70 may be pulled in the direction away fromfront 23 and toward rear 24 of anchor 20. First and second rear portions26, 28 are compressed together by locking ring 70, thus securing suture40 within. Teeth 32 may be provided to insure secure gripping of suture40. As illustrated in FIG. 6, a groove 72 on locking ring 70 may beprovided for seating on tip 29, to secure locking ring 70 in place.

[0035] Referring specifically to FIG. 5, as illustrated, in the openposition locking ring 70 sits between front section 23 and rear section24. An insertion tool (not shown) may engage a recess or protuberance(not shown) in rear surface 74 of the locking ring 70, in order to aidin pulling locking ring 70 to the closed position, as illustrated inFIG. 6. Also, because middle section 25 of anchor 20 provides a recessin which locking ring 70 sits while in the open position, locking ring70 need not be physically connected to anchor 20. Alternatively, afrangible portion (not shown) may be used to secure locking ring 70 toanchor 20. The frangible portion would be broken as locking ring 70 ispulled back to the closed position.

[0036]FIGS. 7 and 8 illustrate an embodiment of a suture locking deviceemploying a push locking ring. FIG. 7 illustrates the push locking ring60 with the device in the open position. As with the embodiment shown inFIGS. 5 and 6, anchor 20 may be provided with a rear section 24 whichhas been split into first and second rear portions 26, 28, defining slitgap 30. A locking ring 60 is disposed around rear section 24. Whenlocking ring 60 is pushed toward the front section 23 of anchor 20, thelocking ring compresses rear portions 26 and 28 together, locking suture40 therebetween. As with the pull locking ring embodiment illustrated inFIGS. 5 and 6, the anchor 20 may be provided with teeth 32, in order tobetter secure suture 40. Once locking ring 60 is in the locked position,lip 34 may be provided to lock edge 62 in place and restrain lockingring 60 from moving back to the open position. As illustrated, edge 62is recessed from rear surface 64. However, edge 62 may protrude from orbe contiguous with rear surface 64.

[0037] Still referring to FIGS. 7 and 8, rear surface 64 of locking ring60 may be provided with a recess (not shown) for use with an insertiontool (not shown). Also, locking ring 60 may be connected to anchor 20 bya frangible portion 66. When force is placed on locking ring 60, thefrangible portion 66 would break, and locking ring 60 would slip intothe locked position shown in FIG. 8. An alternative location for thefrangible portion is illustrated as frangible portion 66 a, althoughmany other locations are possible. Alternatively, locking ring 60 may beconnected by a tether (not shown). In still another alternativeembodiment, locking ring 60 need not be physically connected to anchor20, and locking ring 60 may be inserted simply by pushing it alongsuture 40.

[0038]FIG. 9 illustrates an embodiment of this invention which employs asnap groove. As with the locking ring embodiments, rear section 24 ofanchor 20 is split into first and second portions 26, 28, defining splitgroove 30. A tooth 36 is provided on first portion 26, while a matchinggroove 37 is provided on second portion 28. Suture 40, which has beeninserted through cannula 22, also extends between tooth 36 and grove 37.When tooth 36 is snapped into groove 37, suture 40 is capturedtherebetween and becomes locked into place. It is understood that, whilea singular tooth and groove are illustrated in FIG. 9, embodimentsemploying multiple teeth and grooves are within the scope of thisinvention.

[0039] A wedge design may be used, as illustrated in FIG. 10. In thisembodiment, anchor 20 is provided with cannula 22. A wedge 50 is shapedto fit snugly within cannula 22. Wedge 50 may be partially cannulated,as illustrated with cannulae 52. As illustrated, suture 40 may bethreaded through cannula 22 of anchor 20 and then through cannulae 52 ofwedge 50. As illustrated, suture 40 also passes over arch 54. Withtension on suture 40, wedge 50 may be pushed into cannula 22. Suture 40then becomes locked between arch 54 and the inner wall of cannula 22.While the illustrated cannula 22 and wedge 50 are cylindrical, it willbe understood that other shapes may be used. It is also understood thatcannulae 52 are provided only for ease of insertion, and that wedge 50may be provided without cannulations.

[0040] Still referring to FIG. 10, the anchor 20 as illustrated may beused in applications where front section 23 of anchor 20 is to remainflush with the tissue surface. However, it is understood that a wedgesuture locking device may be used in various applications with variousanchor designs.

[0041] FIGS. 11-12 illustrate another embodiment of a locking device ofthis invention. Locking ring 90 is constructed from a series oflaminated sheets 92. The laminated sheets may be bonded or weldedtogether along the circumference 95 of locking ring 90. Slits 93 may beprovided through each of the laminated sheets 92. An aperture 94 isdefined as the intersection of slits 93. Aperture 94 allows suture 40 topass through locking ring 90. As can be seen in FIG. 12, the laminatedsheets are constructed such that if suture 40 is pulled in the directionindicated by the arrow, suture 40 may pass freely with littleresistance. However, if suture 40 is pulled in the opposite direction,slits 93 close as laminated sheets 92 start bending back uponthemselves. Thus, suture 40 is locked into position.

[0042]FIG. 13 illustrates two locking rings of FIGS. 11 and 12 used torepair a defect 101 in a meniscus 100. As illustrated, locking ring 90 ais located at the inner surface 102 of meniscus 100, while locking ring90 b is located at the outer surface 103 of meniscus 100. Locking rings90 a and 90 b secure suture 40 in place, thereby approximating thedefect 101. It should be understood that FIG. 13 is illustrative of justone example of the present invention. Any of the embodiments could beused to approximate such a defect. The various embodiments of thisinvention may be used to secure one or multiple sutures in a widevariety of uses.

[0043] Although the invention has been described in detail withreference to certain preferred embodiments, variations and modificationsexist within the scope and spirit of the invention as described anddefined in the following claims.

1. A locking device for locking a suture in place comprising a lockingring, the locking ring comprising a series of laminated sheets having anaperture formed to allow the suture to pass when pulled in a firstdirection, but formed to lock the suture in place when the suture ispulled in an opposite direction.
 2. The device of claim 1 wherein thelocking ring is affixed to an anchor, the anchor having a cannula formedto allow the suture to pass therethrough.
 3. The device of claim 1wherein the laminated sheets are circular, the locking ring is tubular,and the laminated sheets are bonded to the locking ring at theircircumference.
 4. The device of claim 3 wherein multiple radial slitsare formed in each laminated sheet, the intersection of the slitsdefining the aperture in each sheet.
 5. A device for locking a suture inplace, comprising: an anchor having a cannula through which the sutureextends, the anchor further comprising a rear edge and a front edge; aseries of substantially parallel laminated sheets affixed to the anchor,each sheet having a circumference and each sheet connected to itsadjacent sheet along its circumference, the series of laminated sheetshaving an aperture formed to allow the suture to pass when pulled in afirst direction, but formed to lock the suture in place when the sutureis pulled in an opposite direction.
 6. The device of claim 6 wherein theanchor comprises a biodegradable material.
 7. A method for locking asuture in place against a portion of tissue, the method comprising:providing a first locking device, the first locking device comprising alocking ring having a tissue facing side and an opposite side, thelocking ring comprising a hollow tube having series of substantiallyparallel laminated sheets affixed therein, the series of laminatedsheets having an aperture formed to lock the suture in place when pulledfrom the tissue facing side, but formed to allow the suture to pass whenthe suture is pulled from the opposite side. extending a first end ofthe suture from a first side of tissue, and locking the first end of thesuture in place with the first locking device.
 8. The method of 7wherein the first end of the suture is locked in place by extending thefirst end of the suture through the aperture from the tissue facing sideto the opposite side.
 9. The method of 8 further comprising the step of:extending a second end of the suture through the aperture from thetissue facing side to the opposite side of the first locking device. 10.The method of 9 further comprising the steps of: extending a second endof the suture from a second side of the tissue, and locking the secondend of the suture in place with a second locking device.